Support Strength

I need to temporarily attach a winch (or pulley) at my house's eve to assist in raising a tilt-up tower (for ham radio), and am wondering if I need reinforcement. Here are the details...

The winch will be directly above, but about 2' - 3' back from the tower, which will have about 2' between it and the gutter. I would like to attach it to the rafters that extend out to form the eve, using something (ideas?) across two.

If it matters, I will be very near, but not exactly at (due to what is outside) a load bearing wall.

I think load will be around 320 lbs, but if anyone wants to double check me, here is how I arrived at that figure.

- The tower is 40' long.
- So the pull point lines up horizontally with the winch when erect, the cable will be attached about 17' from the base.
- Obviously, due to the lever effect, the load will exceed the weight of the tower.
- The tower alone weighs 111 lbs. It tapers so there is more weight closer to the base, but for worst-case, I presumed a uniform weight.
- At the top of the tower (point furthest from base when horizontal), add about 100 lbs for the weight of the rotor, mast, and antenna.
- I presumed, for worst case, it would be starting from laying complete horizontal at the ground, but in reality, in order to attach the antenna, it is going to have to be partially tilted and resting on a ladder or some support I make to get the end up about 8' off of the ground.

So, can I do what I want to do at the eve?
If so, do I need to re-enforce?
Any ideas on mounting the winch or pulley?

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Thanks for the reply, but this tower (universaltowers.com model 15-40) is designed to be assembled on the ground and tilted up. It can be climbed with a limit of 200lbs, but it isn't designed for that so the rung spacing is wide. Also, I need to be able to tilt it back down for any antenna maintenance.

Photo

It would be beneficial if you could post a photo of the entire roof. 320 pounds is not a lot of a load and your end two rafters may be able to handle the lateral load but I have to wonder if you can frame a temporary assembly at the far end of the roof and use the entire roof diaphragm to distribute the load. I am assuming that this is a gable roof and the tower is to be at a gable end.

I am not sure but it sounds like the base of the tower will be on a conc. pad on the ground?
If so you may be over thinking this lift.
Two or three men could tilt this into place easily enough, I think.

Even if he has a good anchor point for the winch it will still take three people and each person has a very different yet important task, if any one person screws up someone’s going to get hurt, not to mention equipment or other damage.

For someone coming to internet asking how to do this, I don't recommend this tilt up, there's safer ways to get that antenna in the air.

If it was only the tower, then yes, a couple of guys could walk it up, but not with the weight at the top - not without the help of a winch that could hold the entire weight if necessary. Once you start to get under it as you walk it, you are bearing a lot more weight. Think of yourself as a nut in a nutcracker, moving closer to the fulcrum.

I fully intend on having a couple fellow hams help me tilt it up, so it won't just be me and the winch, though honestly, if the winch mount supports the full load, it seems like it could be done by a single person.

I forgot to point out that the base is bolted, so it is not going to skid out. Tilting up is the *recommended* way of erecting it per the manufacturer. I'd rather not deviate from the manufacturer's recommendations.

Yes, the base is a 4'x4'x4' deep reinforced concrete block. It is a self-supporting tower.

Yes, I have a gable roof, but no, the tower will be behind the house, about 12' from the end, thus only being able to pull from the eve. (I can take a pic tomorrow.) I cannot put it at the gable end, which is more ideal for several reasons, because that puts it closer to the property line than local code permits. That leaves me with this one and only alternative location.

I talked to someone with a similar tower and antenna, and he had a rope over the entire house and pulled it up slowly with his truck. I don't have that sort of room...plus I would fear damaging the roof.